This invention is an improvement over the apparatus disclosed in U.S. Pat. No. 3,496,761. If a plastic container having a dent in a side wall thereof were tested on the apparatus in said patent, the apparatus would reject the container as being defective. Many plastic containers having a dent in the side wall are not defective containers. The inspection apparatus of the present invention has dual spindles instead of a single spindle as disclosed in said patent. One of the dual spindles pressurizes a container before it is tested to thereby blow out any dents in the container whereby a container will not be rejected as being defective merely because there is a dent in the side wall.